1. Field of the Invention
The present invention relates to an image forming apparatus, and more specifically to an image forming apparatus wherein an image is formed on each sheet fed from a sheet feeding section.
2. Description of Related Art
Conventionally, in an image forming apparatus such as a copying machine, a printer, etc., reaction to a sheet transport problem is to run down the apparatus and indicate need for removing the problem sheet from the apparatus. The operator removes the problem sheet from the apparatus accordingly so that the apparatus will be back in a normal condition. Japanese Patent Laid-Open Publication No. 59-74844 discloses that such a problem sheet is moved to a place where the operator can remove the sheet easily.
When it comes to a printer wherein an image is formed on a photosensitive film fed from a magazine, there are more matters to be considered as follows. Even when a film is jammed before an exposure station, in which case the jammed film is still useful, the operator opens the apparatus in order to remove the jammed film, and therefore the film will be exposed and be of no use any more. This is wasteful especially when expensive photosensitive films are used. When a film is jammed at an opening of the magazine where unexposed film are stored, the opening cannot be closed because of the jammed film. When the operator opens the apparatus in this state, all the films stored in the magazine as well as the jammed film will be exposed and be useless.
In an image forming apparatus, generally, a timer and a sensor are used for watching the travel of sheets, and when a sheet is not detected by the sensor within a specified time, it is judged that a sheet transport problem has occurred, and the apparatus runs down. Especially in transporting photosensitive films, which are coated with emulsion, in such an image forming apparatus, such problems often take place because transport rollers cannot nip the films firmly and because the films themselves are slippery. However, there are many cases which can be settled by operating a transport system again, and if the apparatus is so made as to treat such problems automatically, the operator will not have to check inside of the apparatus and to restart the operation whenever a problem occurs.